mirror of https://github.com/fltk/fltk
194 lines
7.1 KiB
C++
194 lines
7.1 KiB
C++
//
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// A simple terminal widget for Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2011 by Bill Spitzak and others.
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// Copyright 2017 by Greg Ercolano.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// https://www.fltk.org/COPYING.php
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//
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// Please see the following page on how to report bugs and issues:
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//
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// https://www.fltk.org/bugs.php
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//
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/* \file
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Fl_Simple_Terminal widget . */
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#ifndef Fl_Simple_Terminal_H
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#define Fl_Simple_Terminal_H
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#include "Fl_Export.H"
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#include <FL/Fl_Text_Display.H>
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/**
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This is a continuous text scroll widget for logging and debugging
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output, much like a terminal. Includes printf() for appending messages,
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a line limit for the screen history size, ANSI sequences to control
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text color, font face, font weight and font size.
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This is useful in place of using stdout/stderr for logging messages
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when no terminal is available, such as when an application is invoked
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from a desktop shortcut, dock, or file browser.
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Like a regular console terminal, the vertical scrollbar 'tracks'
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the bottom of the buffer as new output is added. If the user scrolls
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away from the bottom, this 'tracking' feature is temporarily suspended,
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so the user can browse the terminal history without fighting the scrollbar
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when new text is added asynchronously. When the user returns the
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scroller to the bottom of the display, the scrollbar's tracking resumes.
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Features include:
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- history_lines(int) can define a maximum size for the terminal screen history
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- stay_at_bottom(bool) can be used to cause the terminal to keep scrolled to the bottom
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- ansi(bool) enables ANSI sequences within the text to control text colors
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- style_table() can be used to define custom color/font/weight/size combinations
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What this widget is NOT is a full terminal emulator; it does NOT
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handle stdio redirection, pipes, pseudo ttys, termio character cooking,
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keyboard input processing, screen addressing, random cursor positioning,
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curses(3) compatibility, or VT100/xterm emulation.
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It is a simple text display widget that leverages the features of the
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Fl_Text_Display base class to handle terminal-like behavior, such as
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logging events or debug information.
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Example use:
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\code
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#include <FL/Fl_Simple_Terminal.H>
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:
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tty = new Fl_Simple_Terminal(...);
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tty->ansi(true); // enable use of "\033[#m"
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:
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tty->printf("The time is now: \033[32m%s\033[0m", date_time_str);
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\endcode
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Example application:
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\dontinclude simple-terminal.cxx
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\skip //START
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\until //END
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Style Tables For Color/Font/Fontsize Control
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--------------------------------------------
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Internally this widget derives from Fl_Text_Display, and therefore
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inherits some of its idiosyncracies. In particular, when colors
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are used, the base class's concept of a 'style table' is used.
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The 'style table' is similar to a color mapped image; where each
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pixel is a single value that is an index into a table of colors
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to minimize per-pixel memory use.
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The style table has a similar goal; since every character in the
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terminal can potentially be a different color, instead of managing
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several integer attribute values per-character, a single character
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for each character is used as an index into the style table, choosing
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one of the available color/font/weight/size values available.
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This saves on as much as 3 to 4 times the memory use, useful when
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there's a large amount of text.
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When ansi() is set to 'true', ANSI sequences of the form "\033[#m"
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can be used to select different colors, font faces, font weights (bold,italic..),
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and font sizes, where '#' is the index number into the style table. Example:
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\code
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"\033[0mThis text uses the 1st entry in the style table\n"
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"\033[1mThis text uses the 2nd entry in the style table\n"
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"\033[2mThis text uses the 3rd entry in the style table\n"
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etc..
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\endcode
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There is a built-in style table that provides some
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commonly used ANSI colors for "\033[30m" through "\033[37m"
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(blk,red,grn,yel,blu,mag,cyn,wht), and a brighter version of those
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colors for "\033[40" through "\033[47m". See ansi(bool) for more info.
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You can also supply a custom style table using
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style_table(Style_Table_Entry*,int,int), allowing you to define
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your own color/font/weight/size combinations. See that method's docs
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for more info.
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All style index numbers are rounded to the size of the style table
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(via modulus) to protect the style array from overruns.
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*/
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class FL_EXPORT Fl_Simple_Terminal : public Fl_Text_Display {
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protected:
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Fl_Text_Buffer *buf; // text buffer
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Fl_Text_Buffer *sbuf; // style buffer
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private:
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int history_lines_; // max lines allowed in screen history
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bool stay_at_bottom_; // lets scroller chase last line in buffer
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bool ansi_; // enables ANSI sequences
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// scroll management
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int lines; // #lines in buffer (optimization: Fl_Text_Buffer slow to calc this)
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bool scrollaway; // true when user changed vscroll away from bottom
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bool scrolling; // true while scroll callback active
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// Fl_Text_Display vscrollbar's callback+data
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Fl_Callback *orig_vscroll_cb;
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void *orig_vscroll_data;
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// Style table
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const Fl_Text_Display::Style_Table_Entry *stable_; // the active style table
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int stable_size_; // active style table size (in bytes)
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int normal_style_index_; // "normal" style used by "\033[0m" reset sequence
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int current_style_index_; // current style used for drawing text
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public:
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Fl_Simple_Terminal(int X,int Y,int W,int H,const char *l=0);
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~Fl_Simple_Terminal();
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// Terminal options
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void stay_at_bottom(bool);
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bool stay_at_bottom() const;
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void history_lines(int);
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int history_lines() const;
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void ansi(bool val);
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bool ansi() const;
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void style_table(Fl_Text_Display::Style_Table_Entry *stable, int stable_size, int normal_style_index=0);
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const Fl_Text_Display::Style_Table_Entry *style_table() const;
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int style_table_size() const;
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void normal_style_index(int);
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int normal_style_index() const;
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void current_style_index(int);
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int current_style_index() const;
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// Terminal text management
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void append(const char *s, int len=-1);
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void text(const char *s, int len=-1);
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const char* text() const;
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void printf(const char *fmt, ...);
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void vprintf(const char *fmt, va_list ap);
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void clear();
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void remove_lines(int start, int count);
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private:
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// Methods blocking public access to the subclass
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// These are subclass methods that would give unexpected
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// results if used. By making them private, we effectively
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// "block" them.
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//
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// TODO: There are probably other Fl_Text_Display methods that
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// need to be blocked.
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//
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void insert(const char*) { }
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protected:
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// Fltk
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virtual void draw();
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// Internal methods
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void enforce_stay_at_bottom();
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void enforce_history_lines();
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void vscroll_cb2(Fl_Widget*, void*);
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static void vscroll_cb(Fl_Widget*, void*);
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void backspace_buffer(unsigned int count);
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};
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#endif
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